LCD has the advantages of being small in size, light weight, requiring low voltage, and having low energy consumption that enable it to dominate a broad market in the portable display domain. In particular, the STN (super twisted nematic) LCD possesses unique advantages and it holds a significant market share in the medium to small size LCD market segment.
STN LCD and TFT LCD are similar in that they demand higher display quality and response speed, fewer shadow occurrences, and improved price to performance ratio. Meanwhile, they also have lower energy consumption, higher contrast, lesser cross talk, broader temperature range and faster frame frequency response.
The advent of MLA (multi-line addressing) driver methods has vastly improved the disadvantages of SLA (simple-line addressing) driver methods. MLF methods can significantly improve the aforementioned issues, allowing it to be more satisfactory in meeting application requirements.
The MLA driver methods have continued to improve with the advancement of technology. Currently, the MLA driver methods can be divided into two categories. One is the traditional MLA adjustment methods realized using N*N array algorithms; another one is an improved MLA modulation methods using (N−1)*N array algorithm. In US20040189581 patent application, the Kawasaki company provides an improved MLA driver array algorithm.
In the actual circuitry, it includes a SEG decoder, a BBM (break before make) circuit, a level-shifter and a level-selector, etc. The displayed data is output from the register to the SEG decoder; it is then processed through the decoder and the resulting control signal is processed again in the BBM circuit; then the signal is sent to the level-shifter; after the level is shifted, it is output to the level-selector to select the segment driver voltage; then the signal is output to the LCD panel to attain the displayed data. When processing a signal, the SEG decoder first conducts the decoding, then performs field processing and the inverse operation (from 1 to 0, or from 0 to 1) as it is described in the November, 2003 technology magazine <Research & Progress of SSE> article titled “Design of LCD Multi-line Selection Driver IC”. To first decode (meaning to first perform array algorithm) requires each field to have its corresponding decoder circuit that specifically performs the matrix operation and thus resulting in complicated decoder circuitry; moreover, the original circuit that is used for matrix operation utilizes multiplication and addition circuits or dynamic circuits and thus these circuits themselves are already complicated, having large surface area and high energy consumption. Therefore, it is desirable to have methods allowing for simplified circuitry, low energy consumption, low cost, and easy to realize segment driver circuits for a LCD driver system.